Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > Exhaust and performance woes

[ells]

Well,

took the old bike down to the dyno. Would you believe it 42bhp!!!!!!!!!!!

Well after a lot of poking at the bike and reviewing air / fuel ratio we have decided to modify the exhaust and then reject the carbs if required.

So my local dyno man has invited his pipe bending buddy over tomorrow and they are going to come up with a plan. I see the problem area being that the right hand exit from the 2 into 2 headers has been cut and welded.

His plan is to try and get front and rear cylinder pipes of equal length and then just push it through the same link pipe and silencer.

Does this make sense? If its all going through one link pipe to the silencer should it be larger diameter??


All suggestions greatly appreciated

Mark

[bradders]

why I went back to 2-1-2 standard

[brummydave]

mark its important to get a larger diameter pipe at the point where the pipes join,to allow the expanding gases to carry on flowing,its hard to get the header lengths equal but allowing the gases to expand negates this prob,have a look at mine next meet,it is ugly as hell but puts out 52.8 on the dyno,
dave

[bradders]

probably where mine went wrong; we used what looked like std pipe size, maybe a tad larger, then into 50mm as it arrived at the end can

[skidlids]

If you can't get the rear pipe as long as the front wouldn't having it made in a larger diameter to give it a equal volume do the job.
At least the exhaust only has to deal with two gas discharges for every two rotations of the crank (unless we're talking about my 620 lst Saturday at Snett, nothing another ECU set of Clocks and a key transponder couldn't fix), so has a bit more time to deal with them than a IL4 does.
Standard 600SS header pipes worked well on my class B bike when fitted with a decent can, put it up at the 52bhp mark.

[Ghost]

Originally Posted by skidlids

If you can't get the rear pipe as long as the front wouldn't having it made in a larger diameter to give it a equal volume do the job.
At least the exhaust only has to deal with two gas discharges for every two rotations of the crank (unless we're talking about my 620 lst Saturday at Snett, nothing another ECU set of Clocks and a key transponder couldn't fix), so has a bit more time to deal with them than a IL4 does.
Standard 600SS header pipes worked well on my class B bike when fitted with a decent can, put it up at the 52bhp mark.

Works for Jumbo Stevenson also.

[ells]

Kev and Phil,
my preference would be for standard headers and decent silencers. However having watched the bay Monster headers and decent silencers are not coming up cheap. Mr exhaust man is looking about £100 (final figure dependant on design) there is no way I could get monster headers and decent silencers for that.

As the header has had its right exit welded up I would need headers and silencers so getting someone to modify the current setup is the current choice but we will see what happens.

Thanks.

[skidlids]

Mark I may have a standard front header I will route around in the workshop over the weekend and see what I have

[ells]

Originally Posted by skidlids

Mark I may have a standard front header I will route around in the workshop over the weekend and see what I have

Thanks,
but unfortunatelly to return it to standard (standard headers and two silencers) I would need most of the header pipework and two link pipes plus two silencers.

After a lot of head scratching and following exhausts on flea bay getting a man who can to adapt whats there seems best. I have been following silencers for a while but nothing came up at a bargain.

Also this guy can slot the work in and around when I am out on track.

Many thanks
Mark

[skidlids]

Originally Posted by ells

getting a man who can to adapt whats there seems best.

Thats what I did in the end, as I wanted to junk one of the silencers, so I had a local guy make me a new 2 into 1 collector, that allows me to use original 900SS headers after cutting off the cross-over/ 4-way collector on the down pipe

http://www.ducatisportingclub.com/at...3&d=1260016492

http://www.ducatisportingclub.com/at...1&d=1260016466

http://www.ducatisportingclub.com/at...2&d=1260016482